Chapter 15 Evolutionary Principles: Speciation Flashcards
Natural Selection
The process that results in adaption of a population to the biotic and abiotic environments.
Directional Selection
Occurs when an extreme phenotype is favored and the disruption curve shifts in that direction.
Stabalizing Selection
Occurs when an intermediate phenotype is favored
Disruptive Selection
Two or more extreme phenotypes are favored over any intermediate phenotype
Fitness
The ability to to produce surviving offspring
Population
All the members of a single species occupying a particular area at the same time and reproducing with another
Microevolution
Small, measurable evolutionary changes within a population from generation to generation
Population Genetics
The various alles at all the gene loci in all individuals make up make up the gene pool of the population
Industrial Melanism
An increase in the frequency of phenotype frequencies
Gene Flow
The movement of alleles among populations by migration of breeding individuals
Mutations
Permanent genetic changes, are the raw material for evolutionary change
Subspecies
Different populations withing the same species
Nonrandom Mating
Inbreeding, or mating between relatives
Assortive Mating
When idividuals tend to mate with those that have the same phenotype with respect to certain characteristics
Sexual Selection
Favors characteristics that increase the likelihood of obtaining mates, and in this way promotes nonrandom mating
Genetic Drift
Changes in the allele frequencies of a gene pool due to chance
Bottleneck Effect
Prevents the majority of genotypes from participating in the production of the next generation
Founder Effect
An example of genetic drift in which rare alleles, or combinations of alleles, occur at a higher rate frequency in a population isolated from the general population
A population consist of 48 AA, 54 Aa, and 22 aa individuals. What is the frequency of the A alleles?
.60 (Hardy Weinberg Equation)
What is the equation for the Hardy-Weinberg priniple?
p^2+2 pq+q^2
Typically, mutations are immediatly expressed and tested by the environment in?
Prokaryotes
The offspring of better adapted individuals are expected to make up a larger proportion of the next generation. The most likely explination is?
Mutations and natural selection
The northeastern elephant seal went through a sevear population decline as a result of hunting in the late 1800’s. The population has rebounded but is now homozygous for nearly every gene studied. This is an example of?
A bottleneck
What generally results in a net gain in genetic variability?
Mutation
A small, reproductively isolated religious sect called the Dunkers was esablished by 27 families that came to the united states from Germany 200 years ago. The frequencies for blood group alleles in this population differ significantly from those in the general U.S. population. This is an example of?
The founder effect
Assuming a population is in Hardy-Weinberg equilibrium, 21% of the population is homozygous, 50% is heterozygous, and 29% is homozygous recessive. What percentage of the next generation is predicted to be homozygous recessive?
29%
When a population is small, there is a greater chance of?
Genetic Drift
What is not expected to help maintain genectic variablility?
Gene flow
The sickle cell allele is maintained in regions where malaria is prevalent because?
The allele confers resistance to the parasite
